An optical signal propagating within an optical fiber may be affected by various dispersion phenomena. Common types of dispersion phenomena include chromatic dispersion, polarization mode dispersion, and modal dispersion. Chromatic dispersion relates to the wavelength-dependency of the rate of travel of an optical signal in an optical fiber, i.e. different wavelengths propagate at different speeds in an optical fiber. Polarization mode dispersion relates to the polarization-dependency of the rate of travel of an optical signal in an optical fiber, i.e. different polarizations travel at different speeds. Especially in long haul transmission systems, e.g. of 40 km or more, chromatic and polarization dispersion can lead to optical pulse broadening and/or intersymbol interference (ISI) that may affect the ability to recover the signal at a receiver.
Modal dispersion may be particularly significant in multimode fibers (MMF) that are widely used for shorter reach applications, e.g. up to several hundred meters. Modal dispersion relates to the modal-dependency of the rate of travel of an optical signal in an optical fiber. In particular, an optical pulse in a MMF may split into several paths (modes) that travel at different speeds. Modal dispersion may lead to optical pulse broadening and/or ISI.
Chromatic dispersion, polarization mode dispersion and modal dispersion may be compensated or controlled in the optical domain using various techniques. Compensation of these and other dispersion phenomena in the electrical domain may be referred to as electronic dispersion compensation (EDC).
Although the following Detailed Description will proceed with reference being made to illustrative embodiments, many alternatives, modifications, and variations thereof will be apparent to those skilled in the art. Accordingly, it is intended that the claimed subject matter be viewed broadly.